( 2.34 ) 
The Top of the Head of the little Hawk Owl , Tl. 62 : The very fmall Spots on the 
Back, Wings, Rump and Tail of the Peacock Theafant , TL 67, and the Middle- 
Feathers of the Tail of the Painted Pheajant , TL 68. Thefe, amongft many 
others, are fufHcient to prove the Practicability of this Method. The fame Sort 
of Varnifh, with a little Lamp-black, is a good Stopper, in Places where the Varnifh 
is accidentally rubbed off, or where any fmall Error or Miftake is committed, and when 
dry may be worked over again to rectify a Miftake. The Piece fhould be thoroughly 
examined, and all OmifHons rectified, before the Aqua Fortis is applied to the Plate. 
A foft Wax for Bordering the Plate to keep on the Aqua Fortis. 
T AKE white Rofin and Bees- Wax in equal Parts, incorporate them together 
over a Fire in a Pipkin, and make the Mixture into a Roll for Ufe. If it be 
found too hard to be worked and kneaded with your Hands in Winter, it may be 
brought to a greater or lefs Degree of Softnefs, by melting it again, with a lefs or 
greater Proportion of Olive Oil. 
When your Plate and the Wax are ready, take a Piece of the Wax, wet your 
Hands, and roll the Wax out in Length like a Cord, fufHcient to go round the 
Borders of your Plate; then lay your Plate in an horizontal Pofition, where it may 
lie firm ; then fix your Wax on its Edges very clofe, that the Aqua Fortis may not 
pafs between the Wax and Plate, then pinch it up to an Edge, and fo make it into a 
Kind of Wall of half an Inch high ; after which pour on your Aqua Forth , a proper 
Sort of which is to he had at moft of the Chemifts Shops in London , and is generally 
too flrong to be ufed without a Mixture of Water. You will know when it is too 
firong, by its almoft boiling on the Plate where it touches the Copper ; therefore 
you are to lower it with Water, till you fee the Bubbles rife very moderately; for 
too great a Strength of Aqua Fortis will break up your Ground, and fpoil your 
Plate. 
When the Aqua Fortis has been on the Plate a little while, (about half an Hour) 
if you perceive by the equal Bubbling? that it has bit kindly, it may be taken 
off, and the Plate clean wafhed with fair Water, and well dried ; then you may 
try the Depth of your Strokes by rubbing off a little Spot of the Ground, and, if 
you find it too faint, put the Aqua Fortis on again; but if you think it has bit 
enough for the firft Time, you may flop (with the before-mentioned Varnifh) all 
thofe Parts that you would preferve light and tender : Let your Varnifh dry a 
little, then put on your Aqua Fortis a fecond Time, and let it lie about halt an Hour. 
It may be taken off, and put on again, if the Cafe requires ; and you may Hop other 
Parts that you would not have very dark, but remember to wafh and dry your Plate 
every Time v a flop with the Varnifh, Few of my Plates have had the Aqua Fortis 
on them lefs' aan half an Hour on the lighter Parts, or more than an Hour and a, 
half on the d arker Parts. When the Plate is bit-in as deep as you would have it, 
wafh the Aqua Fort . well off from it ; then fcrew your Hand-Vice on the Edge of 
it, and hold its Wfc g Side a while before, or over a Fire, and the Wax Border will 
flip off; then take a little Olive, or any Oil, put it on the hot Plate, and rub it over 
. X with 
